what is polypeptide synthesis? | Yahoo Answers
09/03/2008 · What is polypeptide synthesis
"word" in mRNA
is known as a
consecutive nucleotides that specify a
single amino acid
that is to be
For example, consider the following RNA sequence:
It would be read three bases at a time:
And these three codons represent the different amino acids:
UCG- CAC- GGU
Because there are
four different bases,
possible three-based codons (4x4x4 =64)
This wheel shows all 64 possible codons of the genetic code.
Some amino acids
can be specified by
more than one codon.
You start at the center of the circle and move outwards to find the amino acid.
There is also one codon,
, that can either specify for the
amino acid methionine
or serve as the
for protein synthesis.
There are also
three "stop" codons
any amino acid.
Protein synthesis Flashcards | Quizlet
AB - Polypeptide synthesis in three different cell types infected with simian virus 5 has been examined using high-resolution polyacrylamide slab gel electrophoresis, and all of the known viral polypeptides have been identified above the host cell background. The polypeptides were synthesized in infected cells in unequal proportions, which are approximately the same as they are found in virions, suggesting that their relative rates of synthesis are controlled. The nucleocapsid polypeptide (NP) was the first to be detected in infected cells, and by 12 to 14 h the other virion structural polypeptides were identified, except for the polypeptides comprising the smaller glycoprotein (F). However, a glycosylated precursor (F0) with a molecular weight of 66,000 was found in each cell type, and pulse chase experiments suggested that this precursor was cleaved to yield polypeptides F1 and F2. No other proteolytic processing was found. In addition to the structural polypeptides, the synthesis of five other polypeptides, designated I through V, has been observed in simian virus 5-infected cells. One of these (V), with a molecular weight of 24,000 was found in all cells examined and may be a nonstructural viral polypeptide. In contrast, there are polypeptides present in uninfected cells that correspond in size to polypeptides I through IV, and similar polypeptides have also been detected in increased amounts in cells infected with Sendai virus. These findings, and the fact that the synthesis of all four of these polypeptides is not increased in every cell type, suggest that they represent host polypeptides whose synthesis may be enhanced upon infection. When a high salt concentration was used to decrease host cell protein synthesis in infected cells, polypeptides IV and (to a lesser extent) I were synthesized in relatively greater amounts than other cellular polypeptides, as were the viral polypeptides. The possibility that these polypeptides may play some role in virus replication is discussed.